The present invention relates generally to arbitration of access to a shared resource. More particularly, the present invention relates to bus arbitration using dynamic priorities based on the waiting periods of the requests for the bus.
In many technologies, and especially in the arena of electronic computers, a scarce resource is shared among competing interests. For example, a shared bus in a computer is shared among several requestors. In such an environment, an efficient and simple arbitration scheme is desirable in order to increase the utilization of the bus, to increase bus access for the requestors, and to reduce the cost of the computer.
One conventional arbitration scheme simply assigns a fixed priority to each requestor. According to this scheme, access to the bus is always granted to the requestor having the highest priority. One disadvantage of this approach is that the low-priority requestors rarely, if ever, gain access to the bus.